This invention relates to picnic boxes and more particularly to a refrigerator/warmer type box apparatus.
Portable refrigerator/food warmers which operate in cars, trucks, planes, boats, golf carts, and recreational vehicles operating on 12 volt dc systems are known. They are also used with optional 110 volt or 220 volt ac/12 volt dc power adaptor in offices, hotels, dormitories, and cabins.
A known "conduction" type refrigerator/food warmer includes a compartmentalized box having an open top with a hinged lid for closing the top opening. The compartmentalized box has a food compartment and an adjacent thermal heat pump compartment. The food compartment is separated from the thermal heat pump by a metal wall. The metal wall acts as a cold/hot conductive plate for a thermal heat pump for cooling or heating the food compartment. The thermal heat pump polarization is switchable to either cool or heat the metal partition as desired.
This "conduction" type refrigerator/food warmer has a cooling or heating problem resulting from the use of the metal partition as cold/hot plate. The cold/hot plate problem stems from the temperature gradient formed outwardly of the edges of the plate portion to which the thermal heat pump is attached. More importantly the air temperature with the compartment exhibits a large temperature gradient. This temperature gradient is significant enough to cause food spoilage.
An example of the above described device, is the Electric (AC/DC) Portable Refrigerator/Food Warmer, model HN-10 sold by Hsin Nan Enterprise Co. Ltd., Taipei, Taiwan.
While the purpose of the present invention is that of the known devices, the essential difference is that the present invention provides a "convection" type refrigerator/food warmer.